Pallet construction



R. A. FIAETCHER PALLET CONSTRUCTION Dec. 27, 1949 Filed July 24, 1946 4Sheets-Sheet 3 Dec. 27, 1949 R. A. FLETCHER 2,492,626

PALLET CONSTRUCTION Filed July 24, 1946 4 Shets-Sheet 4 y mmal? a mPatented Dec. 27, 1949 orrlcr...

PALLET CONSTRUCTION Ralph A. Fletcher, Westford, Mass.

Application July 24, 1946, Serial No. 685,820

Claims.

This invention relates to transporting materials. More particularly theinvention is concerned with improvements in pallets for use insupporting goods which are required to be moved about and stacked intransit.

The usual pallet construction includes a platform or deck; beams forsupporting the deck in a raised position; and a base for receiving thebeam members. A common arrangement of the beams has been to position twoof these members along two opposite edges of the pallet with a thirdbeam extending parallel to the first two and midway between them. Thisforms a pair of openings extending between two opposite sides of thepallet and with the remaining two sides being closed. Such a structureis referred to in the trade as a "two-way pallet.

A subsequent development has been to substitute relatively small blocksin place of the beam. The blocks are arranged to provide a centralsupport, four corner supports and four intermediate side supportsbetween the corner supports. With this arrangement a pair of openings isformed at all four edges of the pallet and this structure is referred toas a four-way pallet or sometimes as an eight-way pallet.

Both of these pallets have been customarily built of wood in order tomaintain the cost of such devices at a minimum and yet afford a properdegree of strength and durability. When using wood, it is necessary, inorder to secure desired strength, to employ relatively thick plankingand relatively large blocks. This tends to result in a cumbersome body,occupying an undesirably large amount of space andadding con- 4siderably to the weight of a palletized unit. These objectionableaspects of conventional pallets become even more undesirable owing tothe development of a custom of shipping palletized units. Here thepallet may be used only a few times, or possibly only once, and its costmust be absorbed by the party sending the goods. Manufacture ofrelatively light-weight pallets at the lowest possible cost is thus ofparamount importance.

An object of the invention therefore is to improve pallet structures andespecially pallet decks with a view to providing a low-cost pallet whichfurnishes an adequate amount of strength and durability. Another objectis to provide a pallet of outstanding light-weight character and compactconstruction. Other objects will appear from the following descriptionof the invention.

With the foregoing situation in mind, I have designed a fabricated metalpallet structure having much less bulk and weight than theconvcntionalpallets described. As a substitute for the common wooden pallet platformor deck, there is provided a reinforced reticulated deck requiring forits construction substantially less material. similarly in place of theblock supports heretofore used, I have devised skeletonized'columns-andin place of a continuousbase I have provided a number of relativelysmallstrips or plates.

An important feature of the invention there'- iore is a pallet having anopen light-weight deck consisting of a mesh or fabric 'of rigid elementsdisposed crosswise of one another and firmly secured together. Securedto the mesh 7 in a novel fashion are a plurality of reinforcing'elementsextending downwardly fromseveral' points of suspension in the deck toprovide an unusual truss supporting effect. The trussed feature 00-operates with the multilayer construction of a fabric made up ofcross-laid wire-like elements, with the result that tension andcompression stresses, set up in the deck when carrying a load, are moreefficiently distributed throughout the constituent elements of the deckfabric.

In the accompanying drawings:

Fig. 1 is a fragmentary perspective view illustrating a step in forminga pallet deckf Fig. 2 is another perspective view of a furtherdeck-forming step;

Fig. 3 is a detail cross section and partial eleva tion taken on theline 33 of Fig.2;

Fig. 4 is another perspective View;

Fig. 5 is a cross section taken on the line 5--5 of Fig. 4; v I

Fig. 6 is a perspective view illustrating assem bly of base and columnsupport means;

Fig. 7 is a fragmentary perspective view illfustrating the joining ofthe deck and baseman's;

Fig. 8 is an end elevational view of the completed pallet;

Fig. 9 is a side elevational view of the pallet;

Fig. 10 is a detail perspective view of the trussed deck structure; andN Fig. 11 is a perspective view of the fully assembled pallet.

The structure illustrated in the drawings rep-- resents a preferred formof the invention and includes a fabricated deck made up of a pluralityof rigid metal elements secured crosswise of one another to form a meshor grating. The inventlon will be described in connection with a meshdeck formed of steel wire or wire-like elements. It should beunderstood. however, that'the invention is not limited to the particular.deck struc.- ture shown, and that decks fabricated fromother metals,plastic materials and the like may be utilized either in the shape ofrods, strips, sheets or other forms.

In constructing the preferred embodiment of my improved pallet, Iprovide a wire mesh deck (Fig. 1) composed of a plurality of upper deckelements l extending in parallel spaced-apart relation to form a topdeck section, and lower deck elements I! also extending in parallelspaced-apart relation and at an angle to the upper deck elements l0, toform a lower deck section. The elements It and I2 are secured togetherat points of contact as by spot welding, thus providing a continuousnetwork. At the under side of the deck, at separated intervals, islocated a set of truss elements I, one of which has been illustrated inFigs. 2 and 3 of the drawings. The truss elements Ml run at right anglesto the bottom deck wires and are preferably secured by spot Welding. Theelements It also extend all the way across the deck in a straight lineand are secured between two opposite edges to constitute an intermediatesection or thickness of wire lying just below the mesh.

A second set of truss elements it are also located along the under sideof the deck and secured thereto at two opposite edges in the mannershown in Fig. 4. The truss wires it are reversely bent upon themselves aslight amount and extend across and below the truss elements I as notedin Figs. 4 and 5. Those portions of the truss elements It running belowthe truss elements 14 thus constitute a fourth and bottom section orthickness of material in the pallet deck as shown in Fig. 5. It ispointed out that the elements l4 provide a truss effect for the deckelements l2 while the elements It provide a truss effect for the trusselement 14 in an opposite dimension so that a multiple two-dimensionaltruss feature is developed.

The deck assembly described is then temporarily laid aside and a basestructure is assembled. One suitable form of base structure consists ofbase plates l8 formed with corrugations ll} (Fig.

6) Two of these base plates for example are arranged in parallelspaced-apart relation. At their extremities, which are formed withoutthe corru gations 20, are mounted skeletonized columns which form cornersupports. Each column con sists of two U-shaped elements 2e and 22. Thebottoms of the U-shaped elements may be secured to the base plate in themanner shown in Fig. 6 with their legs extending upwardly in parallelrelation. The U-shaped members are further reinforced by means of tiewires 24 and 26, running crosswise of the base plates and occurring atpoints directly below the bent portions of the U-shaped elements. Thereare also secured at the upper ends of the Us two other tie wires 28 and30.v These tie wires have immediately adjacent sides secured to the endsof the U-shaped portions as by welding in the manner already described.These upper tie wires are so positioned that their uppermost curvedsurfaces lie in tangential relation to a plane passing through the endsof the U-shaped portions.

The deck assembly illustrated in Figs. 1-5 inclusive, is thensuperimposed upon the columns in the position indicated in Fig. '7. Inthis position some of the lower deck elements 12 bear upon the tie wires28 and 30 and also are arranged to overlie extremities of the U-shapedelements occurringin each column as may be observed from an inspectionof Fig. '7. Welding is employed to secure the contacting deck wires toboth the ends '4 of the U-shaped elements 20 and 22 and the tie wires 28and 30.

It is pointed out that when the deck elements are thus positioned andsecured, the extremities of the truss elements l6 become interlockedbetween the tie wires 28 and 30 at their under sides and the upper deckwires It] at their upper sides. For a portion of their lengths thereforethe truss elements l6 lie in the same plane and deck section as thelower deck wires 12. This in effect provides a point of suspension forthe truss elements from the edge of the deck. From these suspensionpoints the truss elements pass downwardly under the truss elements M fora substantial distance. It may also be desired to secure the ends of thetruss elements in other ways as directly to one of the mesh wires and atpoints within the edges of the deck. There is, in this manner, obtaineda multiple trussing construction which is peculiarly adapted to moreefliciently supporting a paletized unit. A further modification mayconsist in using short slugs or spacing el ments in place of the trusselements M.

I may also desire to secure along the edges of the deck outer frameWires 34 and 35 as noted in Figs. 7 and 11. The ends of the frame wiresmay conveniently be passed downwardly in a diagonal direction and besecured to the base plates l8 adjacent to the U-shaped elements 20 and22. Other arrangements may also be resorted to, for example thereinforced deck may be secured to other types of supports such as shortpipe sections and the like, used with base plates or independently ofthem, and in place of the base plate sheet materials, fabricated wiremesh and other substitutes may be utilized. It is intended that thearrangement shown in the drawings may be further varied by suspendingsome or all of the truss elements at their extremities only, thuseliminating the central point of suspension. It may also be desired toinsert truss elements at other points and in other ways as for examplecrosswise or diagonally with respect to the pallet deck.

It will be observed that by suspending multiple truss elements in andthrough a mesh deck of the character described, there is obtained alowering of the neutral axis of the deck when carrying a load. This hasdefinite structural advantage for a pallet body especially with across-laid wire-like type of fabric. Thus in a pallet deck formed ofspaced-apart wire-like elements of circular cross section, the wire-likeelements running in any one direction may be considered as a series ofbeams. When a load is placed on these beams, they constitute asupporting structure having a neutral axis passing through the centersof the beams. In a loaded beam of circular cross section such as roundwire of the type referred to here, the greatest amount of metal is thusalong the midportions at the neutral axis where it is not required.There is progressively less metal toward the top and bottom of the beamwhere the compressive and tensile stresses are progressively greater.

Upon adding truss elements and suspending them from the deck, thisaction of the stresses set up in the deck wires from a load isconsiderably changed. As the load is imposed on the trussed deck, thebottom truss element becomes almost entirely a tension member and theoverlying wires take substantially all of the compressive stress. Theneutral axis in this case assumes a position along points between thetruss elements and the other deck wires. By using multiple trusselements, the neutral axis may be further lowered.

It will be apparent therefore that at any typical section of the deck,and especially at the middle of a span occurring between cornersupporting columns, there is a relatively large amount of metal to takethe compressive stress and also a relatively large amount of metal totake the tensile stress; along the neutral axis, on the other hand,there is substantially no metal except for the occasional truss elementM. The trussed construction therefore adds greatly to the strength of areticulated deck because it makes better use of the metal involved. Thispromotes lightness and low cost with sufficient strength to meetrequirements.

In actual practice it has been found that combining truss members with apallet deck in the manner described produces unexpectedly high strength.Thus in a pallet 48 x 48" in which five truss members were employed, itwas found that load-carrying capacity of the deck was increased fourtimes. The requirements for which pallets are built range from one ortwo tons or less all the way up to eight and ten tons. It will readilybe seen that different sizes of pallets may be required and in thisconnection the deck elements and other members may vary in gauge. Oneoutstanding advantage in the trussed deck is the substantial reductionin the gauge of wire or other stock which may be required for carrying agiven range of loads. Reducing the gauge of the wire or other stock hasseveral desirable advantages, principal ones being a great reduction incost of the pallet and a lowering of weight and bulk.

It becomes possible to develop an adequate amount of strength in anexceedingly light, cheap deck fabric, and this in turn makes possiblethe use of such devices for single shipments of palletized units withoutexcessive expense.

Other advantages suggest themselves stemming from my improved reinforcedfabricated pallet deck. For instance, the relatively high degree ofstiffness and strength imparted to the pallet deck by the truss membersgreatly increases the length of span which it is feasible to utilize.This is of considerable advantage since it makes possible the use of alesser number of supporting columns or blocks, and in addition tofurther lightening the pallet, increases its passageway area andfacilitates entry of the lifting forks of trucks employed with pallets.

It is pointed out that the pallet of the invention is provided with onlyfour corner columns whereas it has been necessary in the past to employblocks intermediate the corners or beams running centrally through thepallet.

From the foregoing it will be evident that I have provided a palletstructure having an unusually rigid deck span which by reason of itsfabricated character and trussing features is capable of developing ahigh load-carrying capacity in a lightweight structure, while reducingthe cost of manufacture. As a result there is achieved an efilcientpallet structure which can be manufactured sufficiently cheaply as tomake it feasible to ship goods on these pallets as a unit.

I claim:

1. An improved pallet comprising a wire mesh deck member, means forsupporting the deck member in an elevated position, a set of trusselements suspended from two opposite sides of the deck at pointsoccurring between the supporting means and extending below the underside of the deck, a second set of truss elements suspended from the deckand passing between the said first set of truss elements and the deck,said second set of truss elements extending angularly with respect tothe truss elements of the said first set to provide a two-dimensionalmultiple truss supporting efiect.

2. An improved pallet comprising a wire mesh deck member, meansspaced-apart for supporting the deck member in an elevated position, aset of truss elements suspended from the deck and extending below theunder side of the deck between two opposite sides thereof, a second setof truss elements suspended from the deck at points between saidsupporting means and passing between the said first set of trusselements and the deck, said second set of truss elements extendingangularly with respect to the said first set of truss elements andadditional truss means lying below those portions of the said trusselements of the first set which occur immediately adjacent to theirextremities.

3. An improved pallet comprising in combination a reticulated wire meshsupporting deck, spaced-apart column means for supporting the deck in anelevated position, truss means suspended from those deck portions whichare immediately adjacent to the said column means and arranged tosupport intermediate edge portions of the deck.

4. An improved pallet comprising a mesh deck formed of upper and lowerwire-like elements occurring in spaced-apart relation and laid acrossone another, a plurality of column members for supporting said deck,said column members consisting of pairs of U-shaped legs securedtogether with horizontally extending tie wires, said column membersbeing mounted on separated base plates, a set of truss wires suspendedfrom the deck at two opposite sides thereof, a second set of trusselements running below the first set and at right angles thereto, theextremities of said second set of truss elements being bent upwardly andlying in the same horizontal plane occupied by the lower elements of themesh deck, said extremities further being secured to the said tie wiresof the U-shaped legs.

5. An improved pallet comprising a wire mesh deck, means for supportingthe deck in an elevated position, the means consisting of uprightshaving their upper extremities secured to the deck, truss elementssecured to the under side of the deck and to adjacent upper ends of theuprights, a set of reversely bent truss elements extending below theunder side of the deck between two opposite sides thereof, theextremities of the reversely bent truss elements being secured abovesuch of the said first truss elements as occur along the edges of thedeck and intermediate portions of the reversely bent truss elementsbeing secured below others of the said first truss elements lying inspaced relation to the edges of the deck.

RALPH A. FLETCHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 815,061 Belloff et a1 Mar. 13,1906 1,698,038 Warshaw et a1 Jan. 8, 1929 2,463,587 Arthur Mar. 8, 1949

